Cutting mechanism



A. F. PRESTON CUTTING MEGHANISM Orglgnal Filed May 18.

Patented July 8, `1924.

ALBERT F. PnnSTomnncnAsnn, LATE or nosToixr,A MASSACHUSETTS; BY JOHN ABBOTT, or WINoHEsTERgAND ALFRED 'Buisson`WHITE,v or' Bnooxnmn, MASSACHUSETTS,

AJJMINISTRATORS.

CUTTING MECH-AMSM.

Original application'V led-llray'V 18', 1916, Serial No.' 38,3421 vPatent No. 1,383,023; dated June. $38, 1921.

DividedV and thisa'ppucauon tieaAprn a1; 1921.

VTo all whom` t may: concern Y Beit known that ALBERT F..PBESToN de,- ceasedlatefacitizen of the'United States,` residing. at Boston, in thefcounty of Suffolk. and State: of Massachusetts, invented new and useful. lmprovementsin (luttingMecha?v nism, `of which `the following is. asspecilication.

This invention'. h'asreference t'o` cutting means embodied' ina pair ofcomplemental shearing cutters which' are` particularly intended for. the use,v among others, ofrcutting pieces from sheet `m'aterialf'fni` predetermined.

outlines. Morel particularly the` subjectmatter of they present Yapplication is an. invention divided' from `the prior filed' by Albertl". Preston, deceased, which. has matured into` Patent No.- V1,383,023, dated: June 28,1921-, and the-specific. .use` forwhich `the cutting apparatus is applied in fsai'd parentapplication is for cutting patterns outlofsheet stock similar to amodel patternand either Aof the same .size as', or larger-or smaller' thai1the'r model. InA the combination disclosed inV the.` parent application'the model-land sheet of stock from which'th'e reproduced article isI tog'becut are' mounted" in the same holder, with a space-between them, and are moved in urn-l son' past a guide and' the 1 cutting rnec'hanism,k

respectively7 the edge of the modelL being`A in" contact-with the gui'def and the blank sheet off stock being placed betWeen.the#coun plementalf cutterslso that' itv will be s'heared thereby' onlines similar tof theV outlinesof* the. model.

'Il-he purpose of the present' application to 'protect the invention 'involved inthefnew` features of the cutting means` for any use' to whichsaid cutting means may'bejadapted and Vindependently vrof' itsV association `with the' machine described in the parentlapplication. l

The invention is embodied in two'k cutters of which, rat least, one oft'hem isreciprocated across the edge' of the` other, and one fof' them* `has av Ashort cutting edge in order 'to' permit-of cutting out -pieceson curvedlines.A

The other or'complemental cutter may have a cutting edge-of any `length and iS'1preferably adjustable so as to bring' dillerent parts'of its cutting edge into` cooperation application Serial JNO. 463,292.

l Witli:` theflrst cutter as parts of` such edge become.v dull. -Iir its? most `practical, form `this-fadjustable" cutter is a disk and. is sov shown here.

The. important-new feature ofthe cutting mechamsmfisrthat the-cutter which has the short edge'. is convexf toward theother cutter, while the edge of the other cutter is straight, at leastthe projection-of Such edge on the plane` ofthe Stock'which is being out is straightV point in the curved edge of the one cutter comes approximately tangent to the edge-,of `the complemental cutter, while other. parts* of such curved edge` diverge from the; projection of the complemental cutter. Thereby it becomes possible, in turningV a sheet of stock. so as to cut out a curvedv outline, and particularly such outlineas defines aconcavity in the edge of the article" being.V produced, to enable the tangent point'of the: curved cutting edge to follow `the required'outline. accurately andfwithout 21 and: 3 'are detail sectional views ofsthe- .cutter holder' and' cutter illustrating a novel-:mode of mountingthe V cutter inthe' holder.' Figures and'f are diagrams showing fragments'iof articlesH outlined' by cutting'. `tools, andiifllustrating by :and improved' result accomplished by 'the present improved cutting device.

contrast the. new

Figure ".fiswa plan view much enlargedzof the complemental cutters which constitute the cutting. or shearing device in which my present' invention is embodied.

Tfhe same referencey characters indicate the same `parte in' all the fligures.

The cutter head l2 represents any means :adapted to support and operate complemen- "tal cutters in such .amanner' as to define the outline of, :and sever an article' from', sheet material. @ne-of such' cutters is a .disk 18 secured by `a screw 19 tor-the 'head fixedly,

but'withcapability for being turned to present a fresh sharp portion of its edge to the` complemental cutter when another portion of such edge becomes blunt. The comple.- mental cutter is mounted in a carrier or block 21 and slides in a guideway 22 on the head, soarranged that the end of the cutter 20, on which is the cutting edge, passes back and forth across the nearest part of the i' ed by. the cutting device.

thing'is that the projection of the'v opera` VS27 in the carrier or block 21.

curved, and also Vcurved cutting edge of the cutter 18, said cutters 18 and 2O thus constituting a pair of shears. The cutter 2O is reciprocated rapidly by Va shaft 23, powerv driven which Va driving belt passes, said shaft hav` ing a crank pinQ carrying an anti-friction roll'26 Which travels in a transverse groove In' the cutter head is a spacev 28 to admit the sheet material'being cut when such sheetmaterial is passed between the cutters p18/` @ne of the main improvements embodied in the cuttingfmechanism consists in the fact that the cutting edgeV 37 of the cutter vQOis in the combination of such edge With the straight ledge 38 of the complemental cutter; 18. yln describing-.the edge of the cutter 1-8 as straight I have reference to the projection of such edge on the cuttingfplane, and disregard the circular periphery of the disk, Which has no infiuence Whatever on The essential edge of disk 18 on tivev part of the 'cutting the plane in Which the cutting plane, that'is,

the sheet of stock to Ybe cut is laid, is a edge3 8 of the cutter 18 lies.

bevel at an acuteY straight line 38, and is essentially the same as though the cutter Were a bar having a" literally straight edge,

or polygonal having a periphery made up of short Astraight lines.

The projectionV of the edge 37 of the cutter 2O on the planeofthe stock to be cuty (or. in

other'vvords on the cutting plane) Yis curved,V

and tangent, preferably Vat its -middle point', totheV projection onthe same planeV of the edge of the cutter 18. The cutter 20 lis a bar which is curvedvor rounded, prefer-A ably as the segment of va cylinder, on the the plane in Which the cutting Y*The* end of the side next to cutter 201is ground off on a angle to the rounded side. Incidentally the cutting edge, formed by the intersectionof an inclined plane with a curved surface, is, highest at the middle part, but except for,

the fact that this formation makes it somewhat easier for the cutter to penetrate the stock, lit is of no consequence to the real invention. v

The utility of the :invention is graphically shown in Figures 4 and 5 Which showty respectively, ina somewhat exaggerated Way,

the Character of Work'performed respective ly by the complemental cutters previously by a pulley Qaround' the result accomplish` 'edges` .inclinedfout' of the correct position,

used, both having straight edges, and by my improved cutters. In both figures, a Yrepre- Sents a fragmentfof reproducedgpattern e Complemental straight-edged cuttersare Y incapable of'cutting curved outlines vWith. absolute accuracy because necessarily the outlines thereby cut consist ofstraight YSegments and cannot conform exactlyto curved lines.V In vcutting convex outlines thedeparture from the exact curvature is ummportant, but in cutting concave outlines vcor-Y A responding to armodel the departure is more serious because the corners of the cutter must unavoidably cutmorejdeeplyf into the reproduced article than the `required out-1 V line. That'this'must be so isevidentffromY thelfact that if the straight edge ofthe cutter is tangent to the Vrequired curve at any point in alconcave or .recessedjpart of the.

outline, one orboth cornersof the cutterVv quired curve. A further, difficulty-:has been encountered in that it is difficult to feed the Y stock alvvvays with respect tothe cutter head so that the line to be` cut is always exactly tangent to thefedgeo'f the.cutter, .and fre- .4

V1quently, particularly when cuttingoutsharp- 1 ly concave'parts ofthe outline, this line be- Y comes considerably'inclinedytd .thecutting edge at .the cutting point. ,The result generf ally has been :to cut an outlineA VhavingY notches as ,shownfinfaj somewhat exagg1`;

ated way, in Figuree. This effect is-pa'r-V Y a 155V I must extend into the vstock vvithin the re-V sheet iron and-the like, and insuch stock ng orotherQcharshearing. device ,no fsuchj error? can occur,j

Veven When the'lineonvvhich thepatternuis v'cut is held ata considerableV angle tothe line f tangent to the central point of the,fcutting-V Not. matter hovvA much theV Ypattern fis Y Within limits, the outv `made bythe Vcutter isv ac- :curately placed andis Valways tangentto the correct bounding line `of the article.A Thei piece thereby out is outlined asV shown Which are tangent to.the.; correc`t V bounding line; The-height-of the ridgesgbetvveenthe scallops: is determinedby the-.rateV of feed may, by making the feed slovv' enough, be reduced to lnconsiderable; trifles.1 VIn any event thesepro]ections or ridges can be re- :moved byk b utling, and when thus removed A the resulting smooth edge.conformsexactly 130 Y in Figure 5by a series of scallops, all of `V 'of thestock past the cutting deviceffand'olQ to the correct nished outline required in the piece.

The cutting element or knife l() is removable from the carrier 2l for sharpening and renewal, being contained in a socket 40 open at one end of the block. There are tWo such sockets arranged at respectively opposite ends of the block and opening into `the transverse slot 27 thereof. VThe inner end of the blade rests on a stop 41, and is retained in place by a pin 42 which passes through the block and projects into a notch in the side of the knife. The pin 42 and stop 4l may both be removed when it becomes necessary to take out the knife, the knife being dislodged by an instrument inserted through the alined socket 40 in the opposite end of thel block and pressed against the butt or foot of the knife.

Vhat We claim and desire to secure by Letters Patent is:

l. A cutting apparatus comprising a movable cutter or blade having a curved cutting edge, the projection of which on the cutting plane is curved and a complemental cutter for holding the stock against the thrust of said cutting edge and at one side of the path thereof.

2. A cutting mechanism comprising oompleInent-al shearing cutters one of which has a straight edge and the other a curved edge,

the projection of which on the cutting plane is a curve tangent to the projection on the same plane of said straight edge.

8. A cutting or shearing apparatus comprising complemental cutters one of which has a straight edge and the other has an edge, the projection of Which on the cutting plane is a curved line.

f 4. A cutting or shearing apparatus comprising complemental cutters one of Which has a straight edge and the other has an edge, the projection of which on the cutting plane is a curved line, and one of said elements being movable across the line of the edge of the other element substantially tangent thereto.

5. A cutting or shearing mechanism comprising' a relatively stationary disk cutter having a cutting edge, a complemental cutter having a curved cutting edge and being movable across the cutting edge of the first cutter in a path which brings the central part of its edge substantially tangent to the edge of the rst cutter.

In testimony whereof We have atIiXed our signatures.

JOHN ABBOTT, ALFRED BENSON WHITE, Administrators of the estate of Albert F.

Preston, deceased. 

